In poster presentation 2804349 entitled, “Every Other Week Dosing of TRC105 (Endoglin Antibody) in Combination with Pazopanib in Patients with Advanced Soft Tissue Sarcoma,” updated data were presented from 18 angiosarcoma patients treated with the combination of TRC105 and Votrient, and an additional cohort of six soft tissue sarcoma patients treated with a hybrid dosing schedule of TRC105 and Votrient. Key results included:

TRC105 target concentrations previously shown to saturate endoglin receptors were achieved continuously using a TRC105 hybrid dosing schedule of 10 mg/kg weekly for four weeks followed by 15 mg/kg every other week.

Median progression-free survival (PFS) was 7.8 months in 13 VEGF inhibitor naïve angiosarcoma patients treated with the combination of TRC105 and Votrient using either 10 mg/kg weekly dosing or the hybrid dosing schedule of TRC105. This compares favorably to the median PFS of 3 months reported in a retrospective study of single agent Votrient in patients with angiosarcoma.

In the 17 patients who received prior treatment of metastatic disease, treatment duration on TRC105 and Votrient exceeded the duration of the most recent prior therapy in 7 of 12 VEGF naïve angiosarcoma patients and 2 of 5 patients who received a prior VEGF inhibitor as part of their most recent prior therapy.

Treatment with the combination of TRC105 and Votrient continued to be well-tolerated and allowed for dosing of the combination for more than two years in patients who experienced complete responses to treatment.

“The combination of TRC105 and Votrient continues to demonstrate the potential to deliver meaningful benefits to angiosarcoma patients. We continue to achieve important progress with the clinical development of this compelling product candidate, as our pivotal Phase 3 TAPPAS trial is now open at more than 20 sites in the U.S., and European sites are expected to open by year-end,” said Charles Theuer, M.D., Ph.D., President and CEO of TRACON. “We also continue to evaluate every other week dosing of TRC105 in other indications, including lung and liver cancers.”

TRC105 is a novel, clinical stage antibody to endoglin, a protein overexpressed on proliferating endothelial cells that is essential for angiogenesis, the process of new blood vessel formation. TRC105 is currently being studied in a pivotal Phase 3 trial in angiosarcoma and multiple Phase 2 clinical trials, in combination with VEGF inhibitors. TRC105 has received orphan designation for the treatment of soft tissue sarcoma in both the U.S. and EU. The ophthalmic formulation of TRC105, DE-122, is currently in a randomized Phase 2 trial for patients with wet AMD. For more information about the clinical trials, please visit TRACON’s website at www.traconpharma.com/clinical_trials.php.

About TRACON

TRACON develops targeted therapies for cancer, ophthalmic and fibrotic diseases. The Company’s clinical-stage pipeline includes: TRC105, an endoglin antibody that is being developed for the treatment of multiple cancers; DE-122, the ophthalmic formulation of TRC105 that is being developed in wet AMD through a collaboration with Santen Pharmaceutical Company Ltd.; TRC102, a small molecule that is being developed for the treatment of lung cancer and glioblastoma; and TRC253, a small molecule that is being developed for the treatment of prostate cancer. To learn more about TRACON and its product candidates, visit TRACON's website at www.traconpharma.com.

Forward-Looking Statements

Statements made in this press release regarding matters that are not historical facts are “forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward‐looking statements. Such statements include, but are not limited to, statements regarding TRACON's plans to further develop its product candidates, the potential for TRC105 as a treatment for cancer and expectations regarding the initiation, design and timing of clinical trials. Risks that could cause actual results to differ from those expressed in these forward‐looking statements include: risks associated with clinical development; whether TRACON or others will be able to complete or initiate clinical trials on TRACON’s expected timelines, if at all; the fact that future preclinical studies and clinical trials may not be successful or otherwise consistent with results from prior studies; potential changes in regulatory requirements in the United States and foreign countries; TRACON’s reliance on third parties for the development of its product candidates, including the conduct of its clinical trials and manufacture of its product candidates; whether TRACON will be able to obtain additional financing; and other risks described in TRACON’s filings with the Securities and Exchange Commission under the heading “Risk Factors”. All forward‐looking statements contained in this press release speak only as of the date on which they were made and are based on management’s

assumptions and estimates as of such date. TRACON undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.